Commercial buildings account for about 30% to 40% of the world's energy consumption. It is therefore important to reduce the energy consumption of these buildings. On average, lighting accounts for 40% and heating, ventilation, and air conditioning (HVAC) accounts for 30% of the total building energy use. The remaining 30% is used for appliances, elevators etcetera. It is clear that lighting and HVAC are the main candidates for improvement and the easiest to address.
The three main areas in managing lighting and HVAC are to manage interior lighting, exterior lighting and sun heat gain and to manage the building HVAC system. Each of these systems can be optimized within themselves, already leading to considerable energy reduction. In order to further reduce the energy consumption of commercial buildings, these systems require integration.
However due to business models and building construction processes, these systems have not been integrated in a sophisticated manner. There is thus a need to improve the lighting and HVAC systems of commercial buildings to reduce their energy consumption.
Blinds systems are one type of systems incorporated in commercial buildings for control of sunlight in buildings, affecting both lighting and air conditioning systems. Blinds systems have many mechanical parts that are subject to wear. At the same time it is essential to be able to control the blinds precisely so as to realize maximum comfort and use of daylight, while minimizing glare and uncomfortable contrast levels. An example of the control of a blinds system is shown in the patent publication US-2010/0006241. In US-2010/0006241 a control system controls blinds and lighting in a room dependent on the sun, to utilize the sun light but reduce glare when the sun is strong.
Controlling blinds systems for commercial buildings automatically works quite well, but after a period of use the blinds cannot be properly controlled due to wear in the mechanical parts, e.g. due to stretching of the wires and increasing slag on rotating axes. When a blinds system has been worn, it normally has to be recalibrated, which would normally be done by technical service personnel for the blinds systems or other maintenance personnel, if done at all. Such recalibration is time consuming and expensive and is therefore not done as often as would be desired for optimal performance. The result is that blinds systems often are badly calibrated for relatively long periods of times.